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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Equine immobilization with a limb restraint system

Cai, Wei 14 June 2007 (has links)
Mobility of the horse to initiate motion from the standing position is examined in this thesis. In particular, the thesis focuses on the study of the mobility of a horse with fixed hooves to the ground, and on how its musculoskeletal system is used to free the legs from restraints. Possible leg patterns to initiate motions are investigated. The breaking forces generated at front and hind hooves during static-pulling and dynamic jerking are evaluated. Design of the restraint system that uses ropes to immobilize certain joints in order to prevent the horse from generating these forces is the main objective of this thesis. Such a system could be applied as an alternative to rather massive mechanical devices, the main purpose of which is to block the breaking forces (which are quite large when fully developed).<p> Analysis of the mobility of the horse is based on the mechanics of a skeletal linkage system driven by muscle forces. Only major muscles involved in fighting the restraints are included in the analysis. The force generation capability of a muscle is determined by physiological cross sectional area (PCSA) of the muscle. Possible leg patterns are predicted with the kinematics analysis considering range of motion at each joint in the legs. Corresponding breaking forces generated in each pattern is evaluated with the kinetics analysis. Relationship between the characteristic parameter of the pattern and the breaking force at hoof are established. <p>The horse's computer model is used to justify the analytical result. Fighting mechanisms of the horse are simulated in the dynamic simulation software package. Patterns and the breaking forces developed by the horse model simulation agree well with the analytical results. To the authors best knowledge, this is the first time a computer model is used in analyzing the method of restraining an animal. <p>The mobility of the animal with hoof restraints and methods to remove mobility were further confirmed with a preliminary animal restraint test conducted on a sheep. The sheep was chosen because the leg patterns to initiate motion on a horse are similar to that of sheep, but the sheep is more convenient to handle. The experiment showed that the mobility of the sheep could be removed completely by restraining its hooves, lower legs, and head with easily attached ropes.
52

Cell Polarity Establishment in the Budding Yeast Saccharomyces Cerevisiae

Howell, Audrey January 2009 (has links)
<p>Establishing an axis of cell polarity is central to cell motility, tissue morphogenesis, and cell proliferation. A highly conserved group of polarity regulators is responsible for organizing a wide variety of polarized morphologies. One of the most widely expressed polarity regulators is the Rho-type GTPase Cdc42. In response to cell cycle cues the budding yeast <italic>Saccharomyces cerevisiae</italic> polarizes Cdc42p to a discrete site on the cell periphery. GTP-Cdc42p recruits a number of effectors that aid in the organization of a polarized actin cytoskeleton. The polarized actin cytoskeleton acts as tracks to facilitate the delivery of the secretory vesicles that will grow the bud, an essential process for an organism that proliferates by budding. We have employed treatment with the actin depolymerizing drugs Latrunculin A and B as well as high-speed timelapse microscopy of fluorescently labeled polarity proteins to characterize the assembly of the incipient bud site. </p><p>Often, ensuring that only a single axis of polarity is established is as important as generating asymmetry in the cell. Even in the absence of positional cues dictating the direction of polarization, many cells are still able to self-organize and establish one, and only one, polarity axis through a process termed symmetry breaking. Symmetry breaking is thought to employ positive feedback to amplify stochastic fluctuations in protein concentration into a larger asymmetry. To test whether singularity could be guaranteed by the amplification mechanism we re-wired yeast to employ a synthetic positive feedback mechanism. The re-wired cells could establish polarity, however they occasionally made two buds simultaneously, suggesting that singularity is guaranteed by the amplification mechanism.</p> / Dissertation
53

Laboratory Study Investigating the Three-dimensional Turbulence and Kinematic Properties Associated with a Breaking Solitary Wave

Swigler, David Townley 2009 August 1900 (has links)
A laboratory experiment was performed to investigate the three-dimensional turbulence and kinematic properties that develop due to a breaking solitary and an irregular shallow water bathymetry. A large basin equipped with a piston-type wavemaker was used to generate the wave, while the free surface elevations and fluid velocities were measured using wave gauges and three-dimensional acoustic-Doppler velocimeters (ADVs), respectively. From the free surface elevations, the evolution and runup of the wave was revealed; while from the ADVs, the velocity and turbulent energy was determined to identify specific turbulent events and coherent structures. It was found that shoaling was confined to areas with gentler sloping bathymetry near the basin side walls and the runup shoreward of the still water shoreline was not uniform. The runup was characterized by a jetting mechanism caused by the convergence of water mass near the basin centerline as the wave refracted during breaking. The jetting mechanism caused the greatest cross-shore velocities to be located near the basin centerline. The greatest turbulent events were well correlated to borefronts, resembling hydraulic jumps, where the greatest shear and fluid accelerations occurred. Because of an abrupt change in the bathymetry, a coherent structure developed which was found to have a three-dimensional flow field. It was proposed that variations in the internal flow with depth were due to the orientation of multiple vortex rings.
54

Practicing Community Policing in Penghu County ¡ÐA Study of Operating Model on Police Beat

Hung, Yung-Peng 01 August 2006 (has links)
Abstract The public security is the key factor for a prosperous country; therefore, maintaining a safe social order has always been the most desirous expectation for the public. ¡§Community Policing¡¨ is the strategy to govern public social order, and how to apply its usage is the main stream on crime prevention and police beat is its main core. This study, by reviewing the basic theory of community policing, researching the operational practice domestically and abroad, rechecking the real state of community policing in Penghu, analyzing the recollected data, can be further shaped on its diversified location to develop a satisfactory living space and peaceful land for the Penghu people. By studying this subject, here my suggestions are as follows: ¢¹ Suggestions on community policing of Penghu. 1.Penghu people are quite satisfied with the public security but are still afraid of being stolen. We have to pay more attention on guiding how to prevent the civilian from being a burglar victim and lay emphasis on operational practices. 2.Penghu people are not willing to attend any meeting related to public affairs; the police has to stimulate and inspire the community consciousness of being a civilian by attending any activities or practicing census checks. 3.Implementing sole-duty-beat system can diminish most of the burden of policy duty, which can exclusively make the police more concentrative on doing the census check, providing service, and guiding crime prevention. 4.The success of community policing depends on ¡§close interaction between the civilian and the police; the police must offer high quality service to gain the trust of the civilian. Only by doing this can a close relationship be shaped and be dedicated on crime prevention. 5.The spirit of community policing is beat officer itself; therefore, in order to encourage the officer to persistently manage its beat with diligence and innovativeness, a system based on preventive guiding and service providing to assess the performance of the beat officers is highly requested. 6.While enforcing the community policing, the crucial point to success is decided by how to pass the decision-making to the beat officer, which can make them more flexible and responsive to the need of the community. 7.In hoping of the community policy strategy can keep flourishing, the government authority has to make budget for it and those responsible have to step into the community for a setting up a sound community policing. And the police authority has to make its goal and strategy clear and have a comprehensive communication with the beat officer to build a common consensus. Then , under the process of empowerment, the beat officer can become a member of the community. 8.Twenty-first century is the era of community policing, the police has to cooperate with the medium strategically to publicize the community consciousness, which, in the long run, can be beneficial to build a high quality living environment. . ¢ºSuggestions for follow-up research: 1.Research domain: increase to lay emphasis on community specialty, which can make the managerial strategy more specific and effective. 2.Research object: increase the number of community civilian specimen, which can promote its representation. 3.Research method: increase the observation method as auxiliary, which can be expected to be more adjustable to its location and occasion. 4.Empirical study evaluation : apply ¡§ equalized performance marking card¡¨ to assess the interior and exterior performance of the beat officer, which can be expected to excavate the underneath problems. Key words: community policing, police beat, window-breaking theory, crime prevention.
55

Surface-Wave Propagation on a Gentle Bottom with Lagrangian Form

Huang, Chi-Yang 01 August 2000 (has links)
¡@¡@The main purpose of this paper is to analyze the surface progressive gravity waves propagating on a gentle sloping beach in two dimension. Instead of using the method of Eulerian system by the previous investigators, we introduce the governing equations completely in the Lagrangian system directly. All the characteristics of the wave system is expressed by a suitable perturbation expansion in the bottom slope under linearizing the problem in wave amplitude, then all the governing equations are systematically expanded to order. The solution of the wave system is to be solved to second order , even to high order could also be obtained. Based on the obtained results, the velocity potential, pressure and motion of the fluid particle in the wave system in time and space is therefore presented, and we can see that the bottom slope is a main factor to screw the wave field to deform to break. Finally, the experimental result is cited to compare and verify.
56

Collective Decision-making and Foraging in a Community of Desert Ants

Lanan, Michele Caroline January 2010 (has links)
Ant colonies are often considered to be a superorganism, exhibiting complex collective behaviors, reproducing at the colony level, and dividing functional roles among groups of workers. For this reason, it is often appropriate to study ant behavior at the colony, rather than the individual, level. In this study, I investigated decision-making and foraging behavior in colonies of several species belonging to the ant community of Sonoran Desert scrub habitat. First, I used laboratory experiments to examine how the spatial structure of Crematogaster torosa colonies changes in response to the availability of temporally stable food sources. I found that in this polydomous species the formation of nests is associated with foraging, but that colonies will build broodless structures called “oustations” regardless of food presence. Next, I examined colony spatial structure of a related polydomous species, Crematogaster opuntiae, in the field. I found that colonies used large foraging territories up to three hectares in size, containing up to twenty nest entrances interconnected by a network of trails. Nest location appeared to be related to foraging, with nests located close to extrafloral nectar-secreting cacti (Ferocactus wislizeni) and a negative relationship between cactus density and territory size. Within colonies, forager behavior on neighboring cacti was not independent at short distances, suggesting that separate plants in this system cannot be treated as independent replicates. In the third chapter, I used an individual-based simulation model to investigate the effects of individual worker behavior on the ability of pheromone-recruiting ant colonies to maintain trails to multiple food sources simultaneously. Interestingly, small changes in the behavior rules used by individuals led to large-scale changes in emergent behaviors at the colony level. Lastly, I used field experiments to relate the ability of colonies of three ant species to maintain multiple trails to their ranking in the community competitive dominance hierarchy. I found that the most dominant species tended to forage asymmetrically, whereas the least dominant species exhibited more symmetrical patterns of foraging. The ability of ant colonies to collectively maintain multiple trails may therefore be an adaptive trait linked to the foraging ecology of species.
57

The transfer of momentum from waves to currents due to wave breaking

Weir, Brad January 2010 (has links)
The research presented in this dissertation focuses on understanding the dynamics of waves and currents in the presence of wave breaking. The simplest approach, direct numerical simulation of the ocean dynamics, is computationally prohibitive--waves typically have periods of tens of seconds, while currents vary on times from hours to days. This work uses a multi-scale asymptotic theory for the waves and currents (Craik and Leibovich, 1976; McWilliams et al., 2004}, similar to Reynolds-averaged Navier-Stokes, in order to avoid resolving the wave field. The theory decomposes the total flow into the mean flow (current) and fluctuations (waves), then takes a moving time average of the total flow equations to determine the wave forcing on the current. The main challenge is extending this theory to include a physical model for dissipative wave effects, notably breaking, in terms of the wave age, wind speed, and bottom topography. Wave breaking is difficult to observe, model, and predict, because it is an unsteady, non-linear process that takes place over disparate scales in both space and time. In the open ocean, white-capping often covers less than 2% of the surface, yet still plays an important role in the flux of mass, momentum, heat, and chemicals between the atmosphere and ocean. The first part of this dissertation proposes a stochastic model for white-capping events, and examines the stability of the ensemble average of these events. Near the shore, the decreasing ocean depth causes waves to overturn and break. Over time, this drives currents that erode sediment from beaches and deposit it around coastal structures. These currents are often so strong that their effect on the wave field, and thus their own forcing, is significant. A detailed analysis of this phenomena makes up the second part of this dissertation.
58

Aggressiva barn : -en rapport om barns beteende och pedagogers förhållningssätt

Enghag, Julia January 2010 (has links)
In this report, you will be able to read about how the teacher with the help of others can / should do to support the aggressive pupil towards a more healthy behavior.
59

Lūžio asmenybės: V.Krėvės "Šarūnas" ir "Skirgaila" / Breaking personalities in „Šarūnas“ and „Skirgaila“ by V. Krėvė

Puzinienė, Renata 09 July 2010 (has links)
Darbo tikslas – parodyti ir atskleisti autobiografinį ryšį tarp Vinco Krėvės ir pagrindinių jo dramų personažų – Šarūno ir Skirgailos. Vincas Krėvė – Mickevičius buvo asmenybė, kuriai rūpėjo individas ir jo gyvenimiškųjų vertybių raiška. V. Krėvė pirmasis lietuvių literatūroje pavaizdavo individualią (laisvą, išdidžią, dažnai vienišą ir nesuprastą) asmenybę, suabejojusią visuomeniniais idealais ir susitelkusią į savo problemas. Tokį pasirinkimą lėmė istoriniame procese vis pasikartojantys asmenybės pokyčiai. Rašytoją traukė žmogaus įvairiapusiškumas: meilė ir neapykanta, pasitikėjimas ir nusivylimas, meilė ir kančia, laisvė ir maištas. Šios paralelės labai svarbios ir išryškėja V. Krėvės Šarūne ir Skirgailoje. Darbe aptarti pagrindinių veikėjų charakteriai, jų savybės, akcentuojama autobiografinė V. Krėvės gyvenimo paralelė, aptartos romantizmo ir lūžio (krizės) asmenybės sąvokos. Parodyta, kokią įtaką romantiniam herojaus tipui daro amžinosios (moralinės, romantinės) vertybės, atskleisti prometėjiškumo ir revizionistiškumo raiškos atvejai. / The objective of the thesis to demonstrate and reveal autobiographical relation between Vincas Krėvė and key characters of his dramas: Šarūnas and Skirgaila. Vincas Krėvė – Mickevičius was a personality, who cared a lot about an individual and expression of his true-life values. V. Krėvė was the first in Lithuanian literature to depict an individual (free, proud-hearted, often lonely and misunderstood) personality, who questioned social ideas and was immersed into his own problems. Such choice was determined by personality changes that repeat themselves in the historical process. The writer was attracted by versatility of a person: love and hate, trust and despair, love and distress, freedom and rebellion. These parallels are very important and are emphasized in Šarūnas and Skirgaila by V. Krėvė. The thesis discusses nature of key characters, their characteristics, and emphasizes autobiographical parallel with the life of V. Krėvė, as well as disputes the concepts of romanticism and turning-point (crisis) personalities. The influence of the eternal (moral, romantic) values on the type of a romantic hero is revealed, as well as cases of expression of Prometheism and revisionism.
60

The effect of wave grouping on shoaling and breaking processes

Shand, Thomas Duncan, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Determining the largest breaking wave height which can occur in water of finite depth is a fundamental reference quantity for the design of coastal structures. Current design guidelines are based on investigations which predominantly used monochromatic waves, thereby neglecting group effects which are inherent to the free propagation of waves in deep water. The Coastal Engineering Manual (CEM) states that wave grouping and its consequences is of significant concern, with breakwater armour damage being generally attributed to higher waves associated with wave groups. However, the CEM also acknowledges that there is little guidance and few formulae for use in practical engineering. This thesis describes a laboratory-based investigation into the effect of wave groupiness on wave shoaling, breaking and surf zone processes. New optical-based techniques for data abstraction, developed within this study, have allowed examination of the interaction between deep water intra-wave group processes and shallow water shoaling processes. The applicability of existing methods for predicting breaking wave height and position is evaluated, along with the implications of groupiness on engineering design in the nearshore. The effect of wave groupiness on overtopping and hazard on emerged rock platforms is similarly assessed. Wave group testing has revealed that the spatial phasing of intra-group processes during shoaling can result in considerably different shoaling and breaking regimes. Under certain regimes, wave breaking occurred further shoreward and in a more plunging manner than under other regimes. Within the mid to inner surf zone, waves were also observed to propagate into shallower water before breaking than is predicted by existing design guidelines. This could result in under-prediction of wave height by up to 100%. Expressions are developed for the prediction of maximum wave heights and surface elevation on plane slopes. These expressions implicitly include non-linear group effects and group-induced water-level variations within the surf zone, and are found to provide conservative upper envelopes for the range of data observed within the current testing regimes. Predictive schemes are similarly developed for overtopping hazard on emerged rock platforms based on critical wave and water-level conditions. Variations in maximum overtopping flow values due to intra-wave group processes of up to +/-35% were found. These group effects were found to reduce by up to 30% the threshold wave conditions before the initiation of hazard.

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